Home > Publications database > A real time 155 GHz millimeter wave interferometer module for electron density measurement in large plasma devices |
Book/Report | FZJ-2018-01910 |
;
1982
Kernforschungsanlage Jülich, Verlag
Jülich
Please use a persistent id in citations: http://hdl.handle.net/2128/17700
Report No.: Juel-1802
Abstract: A homodyne, real time 155 GHz Interferometer channel is deseribed which is one module of a multichannei system for use an TEXTOR tokamale A standing sine wave is generated in a phase bridge by transmitting a frequeney modulated millimeter wave down two unequal interferometer branches. The presence of plasma produces a phase Slip of the sine wave with respect to a reference signal. The phase steift is linear proportional to plasma density for expected TEXTOR plasmas. Long plasma paths give multiradian phase shifts which are recorded by a digital fringe counting system. The accuracy of phase measurement is $\Delta \Phi$ = 2$\pi$/16. Phasechanges of 7$\pi$/8 are accepted per modulation period. The microwave in the measurement brauch of the interferometer is transmitted using a quasioptical technique. Components and technical details are described. The interferometer was tested in a simulation set-up and in two different plasma experiments. Experimental results are presented.
The record appears in these collections: |